William a



(No Model.)

W. A. CAMPBELL.

SAFETY VALVE. No. 314,649. Patented Mar. 31, 1886.

UivrTnn STaTns PATENT @rrreE XVILLIAM A. CAMPBELL, OF EAST SAGINAVV,MICHIGAN, ASSIGNOR OF ONE-HALF TO A. F. BARTLETT 8t 00., OF SAME PLACE.

SAFETY-VALVE.

SPECIFICATION forming part of Letters Patent No. 314,6t9, dated March31, 1885.

Application filed September 24, 1884. (No model.)

To all whom, it may concern:

of East Saginaw, in the county of Saginaw and 1 State of Michigan, haveinvented new and use ful Improvements in Safety-Valves; and I do herebydeclare that the following is a full, clear, and exact descriptionthereof, reference being had to the accompanying drawing, which forms apart of this specification.

This invention relates to certain new and useful improvements insafety-valves; and the invention consists in the novel construct-ion andcombination of parts, as more fully hereinafter described.

In the accompanying drawing, which forms a part of this specification,my invention is shown in central verticalsection as connected with theescape-pipe and disconnected from the boiler; and in the drawing, Arepresents the valve-case connected directly with the escape-pipe B andprovided with the usual flange, O, by means of which and suitable boltsand packing the case is designed to be connected with thesteam-generator. This valve-case is divided into two compartments, D andE, as hereinafter mentioned.

F is the orifice in the lower part of the case, communicating with asimilar orifice in the boiler, the two orifices being coincident whenthe boiler and safety-valve are connected together. In the upper end ofthis opening, and in the bottom of the chamber D, there is fitted theswing or poppet valve G, in a seat suitably arranged to receive thesame.-

H is another opening in the wall which separates the two chambers D andE, and this opening is of a much larger area than the opening F, and inthe bottom of the chamber E is seated the valve I, adapted to close anddisclose such opening H. The two valves G and I are connected by meansof a stem, .I, and agnide-disk, K, a little smaller than the diameter ofthe opening H, guides the valve I in its reciprocation.

Vertically through the center of the valves G I, the stem J, and guide Kis an opening or passage, L, which affords the only means ofcommunication between the boiler to which the device is attached and thechamber E.

M is a supplemental valve-case, the bottom the top of the valve I, asshown.-

a of which, when bolted to place, forms the Be it known that LWILLIAM A.CAMPBELL, 1

top of the chamber E, and a spring, N, is inserted between the bottom ofthe case M and An opening, 0, affords communication between the chamberE and chamber P, and at the top of this opening there is seated thewingvalve Q,

and this chamber 1? communicates with the A escape-pipe B by means ofthe connectingpipe R. A yoke consisting of the two studbolts S andcross-bar T is formed in the cham-. her 1?, such crossbar beingvertically adjust able upon the stud-bolts and secured in any desiredposition by means of the nuts U. A spring, V, is interposed between saidcrossbar T and the valve Q.

The device being constructed and attached to the steam-generator asdescribed, it will readily be seen that the steam passing through thepassage L into the chamber E, the area of the valve I being so muchlarger than that of the valve G, would convert the two valves, taken asa whole, into an unbalanced valve so long as valve remains closed, andbalanced when valve Q is open, the pressure being alike upon the underfaceof the valve G and the up per face of the valve I; hence the objector office of the spring N is simply by its pressure to overcome ordestroy the balance after valve Q has closed again. The continuedpressure through the passage L into the chamber E acts upon the valve Q,and the spring V is loaded or set to the pressure the boiler is allowedto carry. As soon as this pressure reaches that point, it opens thevalve Q, allowing the steam from the chamber E to pass through the pipeIt to the escape, and as soon as this is done the pressure in thechamber E is relieved to that extent that the boiler pressure upon thevalve G will cause it audits attachments to overcome the pressure of thespring N, and the steam will escape through the pipe B.

hen it is designed to use this valve upon steamboat engines, or suchengines as are brought within the exercise of law regulating the amountof pressure allowed to be carried, and as the load upon the valve iscreated by the spring V, I provide a cap or cover, W, to thesupplemental case P, which cover I provide with suitable devices, asshown at Y, or their equivalents, for locking such cover in place, sothat no change can be made in the load upon the valve without theknowledge of the inspector, who carries the only means in existence forunlocking such cover.

A passage may be formed-in the case of the valve. which will connect thesteam-space of the boiler with the chamber E; or any outside connectionmay be made between the boiler and such chamber whereby the samepressure is constantly maintained in such chamber as in the generatorwhen the valve Q is closed; and this modification or addition, both ofwhich are shown in dotted lines in the drawings, might be made withoutdeparting from the spirit of my invention; and in this case the passageleading through the lower valve might be omitted, as the same resultwould be produced.

What I claim as my invention is 1. "The combination, with the chambersD, E, and P, and outlets from the chambers P and D,-of the valveG,'c'losing the opening from F to chamber D, the valve I, closing theopening between chambers E and D, a stem connecting and a spring closingboth of said valves, a passage from belowthe valveG to the chamber Ewhen valves G I are closed,

and the valve Q, closing the passage between chamber E and the chamberP, substantially as described.

2. The combination, with the case A, having the orifice F, and thechambers D E P, of the pipes B and R, connecting the chambers D and P,and the valves G I and stem J, having passage L, extending verticallythrough said valves and stem, the spring N, in chamber E, and thespringpressed valve Q, in the chamber P, substantially as described.

3. The combination, with the case A, having the connected chambers D EP, and the pipes B and R, of the connected valves G I,

having the steam-passage L, the spring N, the

spring-pressed valve Q, and the adjustable yoke T, substantially asspecified.

4. The combination, with the case A, having chambers D, E, and P, withinlet F and outlet-pipes B R, and a communication between said inlet andchamber E when the valves G I are closed, of the said valves G I, havingstem J and guide-disk K, the spring N, and the spring-pressed valve Q,in chamber P, substantially as specified. Y

WILLIAM A. CAMPBELL.

Witnesses:

HERBERT A. FORREST, WILLIAM A. DONALDSON.

